Question for an internet outboard mechanic

[Bradenvlp]

Hi - I have an old whaler with a 3 year old Yamaha 50hp that we use to fish and kick around in.

A few weeks ago my teenagers were using it on the lake and it started sputtering and an alarm went off. They were able to sputter back to dock. It has an above deck gas tank that was full of water. Not sure of a crack, unseated cap or a leak in the fitting but it was 1/2 full of water and that water quickly overwhelmed the secondary and primary water separators. Easy fix (replace).

I drained everything, replaced filters, hooked to new gas and after some long cranks it fired, ran rough for a bit then smoothed out and ran like normal (all on a hose in the driveway). Thought I was home free until I checked the oil…. Chocolate milkshake.

I have drained oil and replaced filter (2x) just to get the water out and ran on the hose for about 20 minutes and the oil has stayed clear. But we must have blown a seal somewhere while running on gassy water to end up with it in the oil right?

Seems to me I have an expensive trip to the shop ahead but I thought I’d check to see if anyone wanted to tell me I had nothing to worry about first! If not who’s your favorite Yamaha mechanic between Seattle and Anacortes…

 

[O C Diver]

I really don't like to suggest this, but, I would want to solve the water in the fuel question first. A half full tank of water doesn't sound like a crack or leak. It sounds intentional. If so, did the water in the oil happen the same way?

Ted

 

[Bradenvlp]

Hmmm. Good question. It’s a 14 gallon tank and I don’t really know how much water was in it. A lot. I pulled about a gallon out that was mostly water but was pulling from the bottom. That’s when I decided to take it to hazardous waste and start with a new tank. We had some very heavy rain just before. Not kept in area where someone would be able to easily monkey with it and the brand new Raymarine, tubes etc are all there so I think not nefarious..

 

[SoWhat]

so the teenagers were spinning donuts and the boat & motor ended up under water....
If you drained the oil and gas (and removed the carb float bowl to ensure no water is lurking in hidden corners, you are probably OK.
If it happens a second time, then there is a mystery to be solved. Could be something as simple as gas cap was loose during heavy rain.